[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index][Subject Index][Author Index]

Re: egg development and O-2

> Date: Thu, 04 Aug 2005 06:03:28 -0600
> From: Ken.Carpenter@dmns.org
> [John Vanden Brooks] mentor, Robert A. Berner, the Alan M. Bateman
> Professor of Geology and Geophysics at Yale, characterized the range
> of atmospheric oxygen levels over multimillion year times scales,
> and established an upper value of about 31 percent oxygen, and a
> sharp decline near the Permo-Triassic boundary to about 12
> percent. Earth's current atmosphere is about 21 percent oxygen.

Ken (and others),

Any idea why people always talk about the _percentage_ of oxygen in
the atmosphere?  I'd have thought that the partial pressure would be
more important -- e.g. if the oxygen proportion fell from 20% to 15%
but the total atmospheric doubles, then, wouldn't the partial pressure
rise to 30% of the old total pressure (i.e. 1.5 times the old partial

Or is total atmospheric pressure constant because it's proportional to
g, or something?


 _/|_    ___________________________________________________________________
/o ) \/  Mike Taylor  <mike@miketaylor.org.uk>  http://www.miketaylor.org.uk
)_v__/\  "``user-friendliness'' is over-rated.  If you're not willing
         to learn anything new, you can never use the computer to its
         full potential" -- attributed to Douglas Egglebart, inventor of
         the GUI.

Listen to free demos of soundtrack music for film, TV and radio